Earlier releases of the Institute of Electrical and Electronics Engineers, IEEE, Wireless Local Access Network, WLAN, standards, such as 802.11g, specified 20 MHz wide radio channels for use in wireless communications. These 20 MHz channels are allocated from the 2.4 GHz or 5 GHz industrial, scientific and medical, ISM, band range and occupy defined channel frequencies within the relevant spectrum. More recent specifications of the standard, such as 802.11n, support 40 MHz wide channels (or more such as for 802.11ac), with the goal of increasing data throughput. These newer WLAN specifications specify a primary 20 MHz channel as well as an adjacent secondary 20 MHz channel.
A WLAN access point or AP may broadcast system parameters in its beacon periodically over the primary channel. Newer APs configured to support primary and secondary channel pairings transmit data on a primary channel and, if necessary, simultaneously transmit data on the correspondingly paired secondary channel in parallel, resulting in a higher data throughput and an increase in occupied bandwidth from 20 MHz to 40 MHz. The secondary channel may be considered to “supplement” the corresponding primary channel when exchanging data between a device and the AP. As secondary channels are dynamically added and removed depending on need and availability, the AP typically uses primary channels to transmit management information and other key signaling.
Correspondingly, it is recognized herein that primary channels in a WLAN system are in some sense more important or of higher priority than secondary channels, at least from the perspective of an outside interferer, such as from the perspective of a radio node as contemplated in this disclosure. However, in a common case where the radio node is not configured to decode WLAN transmissions, discerning WLAN channel usage by the radio node is difficult at best, and is made even more problematic because the radio circuitry in such a radio node typically is not matched to the WLAN radio circuitry. Because of the mismatch, the radio circuitry in the radio node may experience signal “leakage” when receiving a signal from a WLAN transmitter, which further clouds the ability of the radio node to discern WLAN channel usage.